rmvb(9f) [opensolaris man page]

rmvb(9F)						   Kernel Functions for Drivers 						  rmvb(9F)

NAME

       rmvb - remove a message block from a message

SYNOPSIS

       #include <sys/stream.h>

       mblk_t *rmvb(mblk_t *mp, mblk_t *bp);

INTERFACE LEVEL

       Architecture independent level 1 (DDI/DKI).

PARAMETERS

       mp    Message from which a block is to be removed. mblk_t is an instance of the msgb(9S) structure.

       bp    Message block to be removed.

DESCRIPTION

       The  rmvb()  function  removes a message block (bp) from a message (mp), and returns a pointer to the altered message. The message block is
       not freed, merely removed from the message. It is the module or driver's responsibility to free the message block.

RETURN VALUES

       If successful, a pointer to the message (minus the removed block) is returned. The pointer is NULL if bp was the only block of the  message
       before  rmvb() was called. If the designated message block (bp) does not exist, -1 is returned.

CONTEXT

       The rmvb() function can be called from user, interrupt, or kernel context.

EXAMPLES

       This  routine  removes  all  zero-length M_DATA message blocks from the given message. For each message block in the message, save the next
       message block (line 10). If the current message block is of type M_DATA and has no data in its buffer (line 11), then remove  it  from  the
       message (line 12) and free it (line 13). In either case, continue with the next message block in the message (line 16).

	 1  void
	  2  xxclean(mp)
	  3	 mblk_t *mp;
	  4  {
	  5	     mblk_t *tmp;
	  6	     mblk_t *nmp;
	  7
	  8	     tmp = mp;
	  9	     while (tmp) {
	 10		      nmp = tmp->b_cont;
	 11		      if ((tmp->b_datap->db_type == M_DATA) &&
				    (tmp->b_rptr == tmp->b_wptr)) {
	 12			   (void) rmvb(mp, tmp);
	 13			   freeb(tmp);
	 14		      }
	 15		      tmp = nmp;
	 16	     }
	 17  }

SEE ALSO

       freeb(9F), msgb(9S)

       Writing Device Drivers

       STREAMS Programming Guide

SunOS 5.11							    16 Jan 2006 							  rmvb(9F)

copymsg(9F)						   Kernel Functions for Drivers 					       copymsg(9F)

NAME

       copymsg - copy a message

SYNOPSIS

       #include <sys/stream.h>

       mblk_t *copymsg(mblk_t *mp);

INTERFACE LEVEL

       Architecture independent level 1 (DDI/DKI).

PARAMETERS

       mp	Pointer to the message to be copied.

DESCRIPTION

       copymsg()  forms  a  new  message  by  allocating  new message blocks, and copying the contents of the message referred to by mp (using the
       copyb(9F) function). It returns a pointer to the new message.

RETURN VALUES

       If the copy is successful, copymsg() returns a pointer to the new message.  Otherwise, it returns a NULL pointer.

CONTEXT

       copymsg() can be called from user or interrupt context.

EXAMPLES

       Example 1: : Using copymsg

       The routine lctouc() converts all the lowercase ASCII characters in the message to uppercase. If the reference count is	greater  than  one
       (line  8),  then  the  message  is shared, and must be copied before changing the contents of the data buffer. If the call to the copymsg()
       function fails (line 9), return NULL (line 10), otherwise, free the original message (line 11). If the reference count was equal to 1,  the
       message can be modified. For each character (line 16) in each message block (line 15), if it is a lowercase letter, convert it to an upper-
       case letter (line 18). A pointer to the converted message is returned (line 21).

	1 mblk_t *lctouc(mp)
	2    mblk_t *mp;
	3 {
	4    mblk_t *cmp;
	5    mblk_t *tmp;
	6    unsigned char *cp;
	7
	8    if (mp->b_datap->db_ref > 1) {
	9	     if ((cmp = copymsg(mp)) == NULL)
       10		      return (NULL);
       11	     freemsg(mp);
       12    } else {
       13	     cmp = mp;
       14    }
       15    for (tmp = cmp; tmp; tmp = tmp->b_cont) {
       16	     for (cp = tmp->b_rptr; cp < tmp->b_wptr; cp++) {
       17		     if ((*cp <= 'z') && (*cp >= 'a'))
       18			      *cp -= 0x20;
       19	     }
       20    }
       21    return(cmp);
       22 }

SEE ALSO

       allocb(9F), copyb(9F), msgb(9S)

       Writing Device Drivers

	STREAMS Programming Guide

SunOS 5.10							    27 Jun 1995 						       copymsg(9F)